Process for preparing cushioning structure using fiber assembly and apparatus therefor

ABSTRACT

A process for preparing a cushion structure by loosening fiber aggregate comprising crimped staple fibers and binder fibers, having a melting points below that of the matrix fibers and dispersed therein, filling the loosened aggregate into gas-permeable mold cavity accompanied with a pressurized air system, and thermoforming the same by heating followed by cooling, wherein the matrix fibers are non-elastomeric, crimped polyester staple fibers and the binder fibers are conjugated staple fibers, comprising a thermoplastic elastomer having a melting point at least 40° C. below that of the matrix fibers and non-elastomeric polyester, the thermoplastic elastomer occupying at least one half of the surface area of the conjugated fibers. When the mold cavity is defined by surrounded area of (1) an upper mold divided into some mold members respectively and independently movable upward/downward, (2) a bottom mold movable upward/downward, and (3) mold frame, the aggregate within the mold cavity can be partially controlled to have a desired compression density even in the step of filling up with the same, at the same time, the aggregate can be uniformly and satisfactorily packed into even a mold cavity having a complicated shape, thereby providing a process and an apparatus for producing a cushion structure which is more inexpensive and has better performance than cushion structures produced by the conventional process in a short time on actually commercial scale.

TECHNICAL FIELD

The present invention relates to a process and an apparatus forpreparing a cushion structure used for such as automobile and airplaneseats, etc. Especially, a process and an apparatus for preparing acushion structure from a mixture of synthetic fibers, in which binderfibers having a melting point lower than that of crimped matrix fibersare dispersed and mixed into the matrix fibers; wherein the fibermixture is transported by entrainment with air flow into a mold cavity,and then turned a fiber aggregate (hereafter expression "a fiberaggregate" used herein is employed to mean "an aggregate of a fibermixture".) into the cushion structure by a heating and a cooling processin the mold cavity.

BACKGROUND OF THE INVENTION

In the arts of preparing cushion structures, foamed polyurethanematerial is well used to form automobile or airplane seats and the like.

However, foamed polyurethane seats have problems that the chemicals usedin the process of its production are difficult to handle and that freonis discharged. Furthermore, because the compression characteristics offoamed polyurethane seats show a unique feature that it is hard at theinitial stage of compression and then abruptly sink down, it not only isscanty in the cushioning property but also gives a strong "bottom-hitfeel". Still more, the seats have little air-permeability andconsequently is apt to become stuffy, which renders the seatsobjectionable as cushion structures in many cases. On top of it, foamedpolyurethane seats are soft and have little resilient power againstcompression because it is foamed. The resilient power can be improved byincreasing ensity of foamed seats, but such also increases the weightand invites a fatal defect that its air-permeability is stillaggravated.

Further, foamed urethane seats generate poisonous gases when it isburned out in the furnace and it is difficult to use for recyclablematerial, then it is longed new material made of the fibers aggregatefor the cushion structure instead of foamed polyurethane seats.

For producing said cushion structures in order to replace said foamedpolyurethane seats, it has been widely practiced to turn the fiberaggregates, which include dispersed and mixed binder fibers in matrixfibers, into cushion structures by the heating and the cooling process.This is to say, the cushion structures are produced by uniting thefibers with the molten binder fibers dispersed and mixed into the matrixfibers, and then the molten binder fibers act as bonding agent to adherethe fibers at their points of intersection. And by adequate selection ofpolymers which form both matrix fibers and binder fibers, the cushionstructures made of the fiber aggregates are expected to be able toreplace foamed polyurethane seats having many defects said above.

In spite of these advantages of cushion structures made of the fiberaggregate, they have disadvantage such as increasing costs, because theyrequire much man-power and excessive time to produce them. Therefore,there are many proposals on method/apparatus to make cushion structuresfrom the fiber aggregates in order to reduce costs and man-power.

For instance, International Patent Application WO91/18828 discloses anapparatus for producing a cushion structures in a gas-permeable moldthrough which suction acts on its all sides in a vacuumed fillingchamber as follows; inducing air flow by said suction; transportingloosened padding fiber aggregate with accompanied air flow into themold; filling up an inside of the gas-permeable mold with said fiberaggregate; and thereafter turning said fiber aggregate into the cushionstructure throughout a heating and a cooling process.

However, such apparatus must adopts a suction means to transport thefiber aggregate into a gas-permeable mold accompanied with air flow,which is induced by a suction which acts on the mold, because of thisreason said apparatus has serious disadvantages as follows.

First, when mold cavity has more complicated shape (especially, when ithas the shape getting deeper), it is very difficult to fill up the eachportion of the mold cavity with the fiber aggregate having desired bulkdensity. Since, when the mold cavity has longer length relative to itsback part to some extend, the fiber aggregate is apt to be accumulatednot only on deepest side of the mold cavity but also on each sides ofthe mold cavity on which the suction acts, and a passage through whichthe fiber aggregate go toward the deepest side of the mold cavity byentrainment with air flow is getting narrower and narrower, and thus theamount of the supplied fiber aggregate to the deepest side of the moldcavity is getting less and less. Moreover, in the worst case, thepassage through to the deepest side of the mold cavity is completelyclosed by accumulated fiber aggregate on the both sides of the passage.In such a case, it is obvious that production of the excellent cushionstructure, having desired bulk density and the amount thereof, is verydifficult, because the fiber aggregate filled up into the mold cavity isless uniform and even has voids, so that cushion structures manufacturedby said method/apparatus is fatal defect.

Secondly, said mold has no means for compressing the filled fiberaggregate actively to adjust compression rate to get the moderate bulkdensity after the filling step is over, because the mold is positionedin a stationary state in the filling chamber. Mainly from this reason,in such a case that different densities are required corresponding toits each portion in the cushion structure, it is no use applying saidapparatus for adjusting the partial density of cushion structure.

Thirdly, it is impossible for said apparatus to stuff the mold cavitywith the fiber aggregate in a state of high bulk density by a suction,because a stuffing force induced by the suction is not so stronger thanthat of compression air.

In U.S. Pat. No. 5,482,665 a method/apparatus is disclosed which doesnot depend on such suction induced by vacuum. In said patent themethod/apparatus uses for introducing the fiber aggregate into a moldcavity by traversing an injector from one side to the other side of themold cavity, so that the fiber aggregate is dispensed onto the femalemold. It is sure that, by using said method/apparatus said above, thefiber aggregate can be dispensed onto the mold cavity of the female moldevenly, but they have fatal problems as follows.

First of all, in such method/apparatus, it is quite difficult to shortenthe filling cycle time of the fiber aggregate into the female mold,because said method/apparatus require a injector, which traverses fromthe one end of the mold cavity to the other end, for filling up a moldcavity with the fiber aggregate in order not to be dispensed unevenlythereon.

Secondly, when the female mold cavity is widened, said method/apparatusrequire a series of injector to cover its all filling area correspondingto its widened mold cavity, and moreover, in this case, saidmethod/apparatus require more complicated device to drive theseinjectors synchronized with each other in order to traverse theinjectors in the same direction. And also, they require ceaselessdownward air flow from the top of the female mold in order to realizeevenly dispensed and accumulated state in the fiber aggregate onto thebottom cavity of the female mold.

Thirdly, the problem takes place when the mold cavity is filled up withthe fiber aggregate in the height direction of the female mold, becauseit causes a problem that a pile of accumulated fiber aggregate is apt tocollapse by the downward wind from the top of the mold. And this problembecomes more serious, as the amount of the supplied air are increased inorder to accumulate the fiber aggregate more evenly onto the bottom ofthe mold cavity, so that the air flow becomes a turbulent flow which isdifficult to rectify. Therefore, the height of the piled fiber aggregateonto the female mold is limited, so, in order to fill up as uniform aspossible with the fiber aggregate in the height direction, it requiresto adjust the height of the piled fiber aggregate and to average it bytraversing the injectors from the one end of the mold cavity to theother end for many times. Because of this reason, it is obvious thatsaid method requires so much time for filling up the mold cavity withthe fiber aggregate, that it is no use for said method expectingtime-shortened molding and cost reduction for making the cushionstructure.

Fourthly, as being easily imaginable, because of requiring for the fiberaggregate to pile up in the height direction, said method has such aserious problem that it can not get the height of the piled fiberaggregate to be high or low partially. Therefore, said method forinserting the male mold into the female mold may be impossible tocontrol a cushion structure having a desired shape to make within onlyone cycle time. Then, in order to partially control the bulk density ofthe cushion structure in its each selected portion, from a viewpoint ofreduction of molding time and cost said method has a fatal problembecause it requires another filling process for filling up a depressionformed at a selected portion, having the higher bulk density than thatof the other, with the fiber aggregate.

Despite the cushion structure made of the fiber aggregate has manyadvantages, in a viewpoint of cost reduction and mass production, it cannot yet replace the same made of foamed polyurethane, because it takemuch time to turn the fiber aggregate into the cushion structure. On theother hand, said formerly, a cushion structure from foamed polyurethanehas many problems, and also it is inferior to that from a fiberaggregate in its performance and character. Therefore, up to now, inspite of having a lot of excellent performance the cushion structuresfrom the fiber aggregate have not been largely produced on a commercialscale for the use of the seat material of automobile, airplane, etc.

DISCLOSURE OF THE INVENTION

The first object in the present invention is to provide a process and anapparatus for preparing cushion structures from the fiber aggregate,being truly produced on a large commercial scale instead of preparingthe same from polyurethane having various kinds of defects. Therefore,for attaining this purpose, cost reduction and mass production must berequired to provide the method and apparatus for turning the fiberaggregate into the cushion structure in a short time in order toeconomically produce it on a large scale.

Moreover, generally cushion structures provided for the use ofautomobile seats or airplane are destined to be repeatedly seated bymany men, so that it is largely and repeatedly deformed and loaded byconcentrated stress at the points of intersection where the fiberaggregate is firmly bonded with each other. In such a case, if thebonding points were rigidly fixed without elasticity, said points ofintersection were easily broken by repeatedly loaded concentrationstress induced by large deformation.

From these reason said above, the second object of the present inventionis to provide process/apparatus for preparing cushion structures formedfrom thermoplastic elastomers, which reduce the concentration stress atthe crossing points where the fibers of the fiber aggregate havethermally bonded with each other, so that it comes to have strongdurability under the repetitive large deformation.

Third object of the present invention is to provide process/apparatusfor preparing the cushion structure having partially changed bulkdensity, within a short time without wasting so much time.

And, fourth object of the present invention is to provideprocess/apparatus for quickly taking out a cushion structure from a moldafter turning a fiber aggregate into a cushion structure.

In order to achieve the purpose said above, in the present invention, werecite a process for preparing a cushion structure, and also recite anapparatus for preparing a cushion structure.

First of all, a method for making a cushion structure in the presentinvention is provided as follows:

A process for preparing cushion structure using fiber aggregate, whereinbinder fibers having a melting point which is higher than that of matrixfibers are mixed and dispersed with the matrix fibers which are madefrom synthetic staple, and that said fiber aggregate is thermally moldedinto the cushion structure having a desired shape by bonding the fusedbinder fibers with the matrix fibers at their crossing points, which ischaracterized in that comprising the following steps of (a)-(e):

(a) conforming a mold cavity having a larger shape than that of themolded cushion structure, whereas the mold cavity is surrounded by a toppart of a gas-permeable upper mold which is movable upward/downward, abottom part of a gas-permeable bottom mold which is movableupward/downward, and a fixed side part of a mold frame;

(b) packing said fiber aggregate into the mold cavity from an open mouthof the mold frame, after loosening a desired amount of the fiberaggregate, by pressurized air with which the fiber aggregate isaccompanied;

(c) compressing the fiber aggregate packed in the mold cavity to desiredbulk density;

(d) binding by the fused binder fibers with the matrix fibers at theircrossing points by passing through heating air, and after heating and/orduring cooling process, further compressing the fiber aggregate to theposition where the cushion structure is finally molded to the desiredshape, while the fiber aggregate is cooled down by cooling air whichflows through the fiber aggregate; and

(e) taking out the cushion structure from the mold cavity by moving thebottom mold downward.

According to the present invention, it is used non-elastomeric, crimpedpolyester staple fibers as the matrix fibers.

And, it is also used elastomeric conjugated fibers composed of athermoplastic elastomer having a melting point of lower than that of thepolyester polymer constituting the staple fibers, by at least 40° C.,and a non-elastomeric polyester, the former being exposed at least at ahalf of the fiber surface.

Herein, said fiber aggregate loosened by a loosening device isintroduced by accompanied air flow, which is induced by pressurize airblown from on the way of a transfer duct and/or which is induced by arotating cylinder of the loosening device, wherein it is important notto directly install in a blower having impellers on the way of thetransfer duct, so that the loosened fiber aggregate can not retrieve theunloosened state by the impact of the impellers.

Thus, the filling process of the fiber aggregate accompanied with thecompression air flow into the mold cavity is carried out. On the otherhand, during the filling process, the fiber aggregate accompanied withthe compression air flow is filled up with from the deepest portion ofthe mold cavity, and then the bulk volume of the fiber aggregate ispartially reduced by downward movement of the upper mold, which isdivided into some mold members both individually and sequentiallymovable upward/downward, corresponding to the partially filled upportions of the mold cavity.

As the divided members of the upper mold said above is independentlymoved downward, the each portion of the fiber aggregate is compressed tothe each desired density corresponding to the each traveled stroke ofthe divided members, and thus the each portion of the molded cushionstructure is controlled to desired density respectively.

And, after the filling process into the mold cavity is completed, asucking process is carried out through the fiber aggregate via the uppermold and/or the bottom mold, so that accumulation direction oflayer-shaped faces of the fiber aggregate in the mold cavity can bepartially rearranged.

Furthermore, before the heating process is carried out, it is veryeffective to repeatedly compress the fiber aggregate filled up in themold cavity in order to randomize the accumulation direction of saidlayer-shaped faces by the reciprocating motion upward/downward of theupper mold.

In addition, with regard to this filling procedure of the fiberaggregate into the mold cavity, which has plural different fillinglength relative to its back part therein, it is apt to cause thegeneration of voids and/or less uniform density distribution of thefiber aggregate in the mold cavity. Therefore, in the case that the moldcavity has said complicated shape, it is important to adjust the mouthwidth of the transfer duct in accordance with changing front-edge widthof the back part in said mold cavity while the fiber aggregate is filledup.

However, it is required for the mold cavity to be filled up with thefiber aggregate accompanied with an air flow, which flows in thedirection intersecting with the right angle relative to the directionwhere the upper and the bottom mold move upward/downward.

And furthermore, in such filling process said above, it is required notto cause the turbulent flow in the mold cavity, and to be filled upevery corner of the mold cavity with the fiber aggregate withoutunevenly filled up portions. Therefore, it is necessary to smoothlyexhaust the compression air, which accompanies the fiber aggregate, fromthe mold cavity by an exhaust device set up in outside of the moldcavity.

Then, it is required to partially adjust each gas-permeability of moldwalls corresponding to flow resistances in the each portion of the fiberaggregate against the penetrating air flow, so that the heating airand/or the cooling air can pass through the fiber aggregate thereinevenly.

Said gas-permeability of the mold walls can be embodied by adjustingdistribution densities and/or sizes of holes wrought in mold walls.

After a series of the process said above were completed, a thermalprocess starts in which the fiber aggregate turns into the cushionstructure by binding the matrix fibers with the binder fibers as abonding agent at their crossing points, and this thermal process iscarried out by the method as follows.

With regard to this process, during a heating and/or a cooling processorafter the heating process, it is desirable that the fiber aggregate iscompressed to a position finally shaped as the cushion structure, sothat heat contraction of the fiber aggregate in the heating and/orcooling process may be absorbed by at least one compressing motion ofthe upper mold and/or the bottom mold.

And also, in order to shorten the molding time in the heating process, aquantity and/or a temperature of the heated air passing through thefiber aggregate are adjusted to over multiple grades in a thermalprocess in which the fiber aggregate turns into the cushion structure.

Moreover, the cooling air is passed through the heated fiber aggregatefrom downward to upward, so that said fiber aggregate can stick to theupper mold by the wind pressure of the cooling air, and the cooling airis suspended after downward motion of the bottom mold, therefore finallythe cushion structure is took out to fall it down from the mold cavityby an action of the gravity.

With regard to this, the cushion structure may not fall down only by itsown weight because of adhering to the upper mold. in such a case, thepresent invention provides a process for spraying compression air overthe cushion structure from a top of the upper mold after the cooling airflow has suspended.

In addition to a temperature of the cooling air is preferable to be aslow as possible, such a temperature as by at most 40° C., in order toeffectively cool down the cushion structure.

Next, an apparatus for preparing a cushion structure to state in thefollowing is provided in order to carry out the method said above formaking a cushion structure.

Namely, the present invention provides an apparatus, which comprises atleast the following elements (a)-(h), for preparing a cushion structureby heat molding from synthetic staple fiber aggregate having matrixfibers in which binder fibers is dispersed and mixed.

(a) a loosening devise for getting the fiber aggregate in a loosenedstate,

(b) a fixed mold frame which has an open bottom and a open top, andconsists the side mold wall by itself,

(c) a gas-permeable bottom mold, movable to the open bottom of said moldframe, for closing said open bottom;

(d) a gas-permeable upper mold divided into some mold members,independently movable upward/downward to the open top, for closing saidopen top,

(e) a transfer duct for transporting the loosened fiber aggregate into amold cavity surrounded by the mold frame, the bottom mold, and the uppermold respectively,

(f) an air supply device for supplying compression air to the transferduct from an air supply pipe opened to the transfer duct,

(g) a heating air generator for generating heating air which flowsthrough the gas-permeable upper mold, the fiber aggregate filled up inthe mold cavity, and the bottom mold respectively, and

(h) a cooling air supply device for supplying cooling air, which flowsthrough the gas-permeable bottom mold, the fiber aggregate filled up inthe mold cavity, and the upper mold respectively, to cool down thefilled fiber aggregate in the mold cavity which is heated by the heatingair supplied from said heating air generator.

Here, in the present invention, it is important for said apparatus toequip with the upper and the bottom mold having holes, of whichdistribution densities and sizes are desirably adjusted in accordancewith each compression degree of the fibber aggregate compressed by eachmold member of the upper mold.

In addition to said apparatus, it is desirable that the apparatuscomprises an adjustment device for adjusting the mouth width of thetransfer duct in accordance with changing front-edge width of a backpart in the mold cavity while the fiber aggregate is filled up.

Also, in the cooling air supply device of the present invention, it actas a device for supplying the cooling air flow which flows from downwardto upward while penetrating into the fiber aggregate.

it is important for said apparatus to further comprises an auxiliary airexhaust device, which is installed in a gas-permeable side wall of themold frame as a forming part of the mold cavity, for exhaust thecompression air supplied by the air supply device from the mold cavity.

Here, said auxiliary air exhaust device is installed in the outside ofthe mold frame confronting to the opened mouth of the transfer ductconnected with the mold frame.

Further, the apparatus of the present invention equips with actuatorsrun by fluid pressure, as means for actuating the upper mold dividedinto some mold members and the bottom mold both movable upward/downwardrelative to the mold frame, wherein said actuators have positioningdevices for controlling each moving position of the divided mold membersof the upper mold and/or the position of the bottom mold in order tocompress the fiber aggregate for multiple stages.

Next, in the apparatus of the present invention, in order to make theaccumulation faces of the fiber aggregate parallel along the moldsurface, it further comprises an air suction device for sucking insideair of the mold cavity from the bottom through the filled fiberaggregate.

Moreover, in order to help the cushion structure adhered to the uppermold to fall downward, the apparatus of the present invention furthercomprises some air spray nozzles for spraying compression air over thecushion structure from the top of the upper mold.

And finally, downward, in order to take out the cushion structure fromthe mold cavity, the apparatus of the present invention furthercomprises a tray, movable to below the mold cavity, for receiving thefalling cushion structure after moving the bottom mold downward.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematically illustrated front views of an apparatus of thepresent invention for making a cushion structure from fiber aggregate,

FIGS. 2(a) and (b) are schematically illustrated front views ofprocedures for filling up a mold cavity with the fiber aggregateaccompanied with a compression air flow, and these figuresdiachronically show the state that the fiber aggregate is sequentiallyfilled up from a back part of the mold cavity through the state of theshown FIG. 2(a) to that of the shown FIG. 2(b),

FIGS. 3 (a) and (b) schematically show the enlarged front views whichillustrate the state that the layer-shaped accumulation faces of thefiber aggregate filled up in the mold cavity are run parallel along themold surface, where FIG. 3(a) shows a accumulated state of the fiberaggregate before suction, and FIG. 3(b) shows that of during suction,

FIG. 4 is a perspective view of an apparatus which schematically showsan adjustment device for adjusting mouth width of the transfer duct inaccordance with changing front-edge width of the back part in said moldcavity, which has plural different lengths relative to a back part,

FIG. 5 is an explanation figure which illustrates the action and effectof the adjustment device (shown in FIG. 4) while the fiber aggregate isfilled up in the mold cavity, which has different filling lengthsrelative to a back part herein, then FIGS. 5(a) and 5(b) are a frontview and a plane one respectively, FIG. 5(c) is a plane view which showsan example of a desirable method for filling up the mold cavity with thefiber aggregate without said adjustment device and FIG. 5(d) is a planeview for explaining the problem caused by a method which is not appliedto the present invention,

FIG. 6, with regard to explanation of gas-permeability through thegas-permeable mold, illustrates plural walls, picked up from each mold,which form the mold cavity (in other words, the part of the mold whichsurrounds the fiber aggregate), herein, FIGS. 6(a) and 6(b) are apartially broken perspective view respectively shown the each case thatthe gas-permeability through the mold is not partially changed and ispartially changed,

FIG. 7 is a schematic front view which shows the state of partiallycompressed fiber aggregate in the mold cavity in accordance with eachrequired compression ratio in respective portion of the fiber aggregate,

FIG. 8 is a schematic front view which shows the state of the fiberaggregate compressed to a position where it is finally turned into acushion structure in the thermal process, and

FIG. 9 is a schematic front view which shows the aspect to take out thecushion made from the fiber aggregate after the thermal process, byspraying compression air from the top of upper mold over the cushionstructure stuck to the upper mold, then by falling it down, and finallyby receiving it on a tray.

OPTIMUM EMBODIMENT FOR PRACTICING THE INVENTION

The optimum embodiment for practicing the invention is hereafterexplained more specifically in further details.

In the present invention, the fiber-crossing portions bonded by themolten binder fibers are formed of resilient thermoplastic elastomer,and these portions are eased from concentrated stress, thereby, as ithas already been stated, it is desirable to make a cushion structurewhich has huge durability under repetitive large deformation.

In order to achieve this purpose, in the present invention, the matrixfibers constituting one member of the fiber aggregate are preferablymade of the non-elastomeric, crimped, polyester, staple fibers. And, thebinder fibers constituting the other member are preferably made of theelastomeric, conjugated, staple fibers, which are composed of athermoplastic elastomer having a melting point of lower than that of thepolymer of the polyester staple fibers, by at least 40 degrees, and anon-elastomeric polyester. Wherein, the said conjugated fibers areoccupied by said thermoplastic elastomer at least at a half of the fibersurface. Thus, by using said fiber aggregate the non-elastomericpolyester staple fibers where thermoplastic elastomer contact at thecrossing points are bonded with the molten thermoplastic elastomer.

And it is also important in the present invention to use the conjugatedstaple fibers, which partially contain thermoplastic elastomer insteadof fully contained one. Because it is sufficient for the binder fibers,in its containing rate of thermoplastic elastomer, to contain thenecessary quantity which act as the fiber-fiber bonding agent in fusingstate. However, in the binder fibers fully made of heat bondingcompound, it is necessary for the binder fibers to increase theopportunity to intersect with the matrix fibers, by intervening thebinder fibers into the matrix fibers, in order to bond sufficiently witheach other. In this case, more than binder fibers which is required mustbe mixed and dispersed into the matrix fibers, then if a large quantityof the thermoplastic elastomer is used as the heat bonding agent, it isso expensive that a cushion structure made by said material loose thecost competition power with that of the conventional urethane foams.

Whereas, according to the present invention, the binder fibers made ofthe conjugated staple fibers, as non-elastomeric polyester fibers beingexposed at least a half of the thermoplastic elastomer, is used insteadof fully thermoplastic elastomeric fiber so that the use quantity ofthermoplastic elastomer may be reduced consequently. Moreover, incomparison with the case that fully thermoplastic elastomeric binderfibers are used, the binder fibers of the present invention make itpossible to reduce the use quantity of the expensive thermoplasticelastomer, and also make it possible to mix and disperse it into thematrix fibers consequently.

Furthermore, according to the present invention, it is easy to increasethe quantity of the binder fibers mixed and dispersed into the matrixfibers at a low cost than conventional one composed of the fullythermoplastic elastomer, and it is possible to increase thefiber-crossing points between the matrix fibers and binder fibers,consequently also to increase the fiber-fiber bonding portions, so thatthe performance of a cushion structure may be improved.

Thus, in spite of partially composing expensive thermoplastic elastomer,by the present invention it comes to realize to make the cheaperreplaceable cushion structure from conjugated fibers than that from theconventional urethane foam.

Herein, according to the present invention, the synthetic staple fibersconstituting the matrix fibers of the fiber aggregate, which are notspecifically limited, include ordinary staple fibers formed ofpolyethylene terephthalate, polybutylene terephthalate,polyhexamethylene terephthalate, polytetramethylene terephthalate,poly-1,4-dimethylcyclohexane terephthalate, polypivalolactone, and theircopolyesters; blends of such fibers; and conjugated fibers formed of atleast two of above-mentioned polymer components. The filament could haveany cross-sectional shapes such as circular, flattened, modified orhollow. The size of the filament preferably ranges from 2 to 500deniers, particularly from 6 to 300 deniers. When the deniers of thefilament is too small, density of the cushion structure increases tooften impair elasticity of the structure as a whole, whereas when thedeniers is too large, handlability of the fibers, particularlymoldability of the fiber aggregate, is impaired. Further, the number offibers forming the matrix becomes objectionably small, to reduce thenumber of the crossing points formed by them and the elastic conjugatedfibers, which results in poor elasticity development in the cushionstructure and concurrently in reduction of durability.

In said case, it is desirable that the matrix fibers have given thecrimped shape, and is future desirable to have given the concretelycrimped shape, in such case, said crimped shape is embodied by themechanical method such as a crimper etc., the anisotropic cooling methodduring the spinning process, or the heating method of eitherside-by-side type or eccentric sheath-core type conjugated fibers.

On the other hand, the elastomeric conjugated fibers as the binderfibers which play an important part in the present invention are likelyused, and said elastomeric conjugated fibers are the conjugated staplefibers composed of a non-elastomeric polyester and a thermoplasticelastomer, which have a melting point lower than that of polyesterconstituting the matrix fibers by at least 40° C. Wherein, it isdesirable that the conjugated staple fibers are exposed by the saidthermoplastic elastomer at least at a half of the fiber surface. Interms of weight ratio, it is convenient for said binder fibers to havesuch a conjugation ratio of a thermoplastic elastomer to anon-elastomeric polyester as that of 30/70 through 70/30. The structureof the elastomeric conjugated fibers may be either side-by-side orsheath-core form, but the latter is more preferred. In the case ofsheath-core structure, naturally the non-elastomeric polyester serve asthe core which may be concentrically or eccentrically located. Eccentrictype is the more preferred, because it develops coil-formed elasticcrimp.

As the thermoplastic elastomers, polyurethane elastomers and polyesterelastomers are preferred.

Polyurethane elastomers are those obtained through reaction of alow-melting polyol having a molecular weight in the order of 500 to6,000, e.g., dihydroxypolyether, dihydroxypolyester,dihydroxypolycarbonate, dihydroxypolyesteramide or the like; with anorganic diisocyanate having a molecular weight not higher than 500,e.g., p,p'-diphenylmethane diisocyanate, tolylene diisocyanate,isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate,xylylene diisocyanate, 2,6-diisocyanate methylcaproate, hexamethylenediisocyanate, etc.; and with a chain-extending agent having a molecularweight not higher than 500, e.g., glycol, aminoalcohol or triol. Of suchpolymers, particularly preferred are the polyurethanes, for thepreparation of which polytetramethylene glycol, poly-ε-caprolactone orpolybuthylene adipate is used as the polyol component. In this case,preferred organic diisocyanate component is p,p'-diphenylmethanediisocyanate, and the preferred chain-extending agent isp,p'-bishtdroxyethoxybenzene or 1,4-butanediol.

Those useful as the polyester elastomers are the polyether/ester blockcopolymers formed through copolymerization of thermoplastic polyestersas the hard segments and poly(alkylene oxide) glycols as the softsegments. More specifically, the copolymers are dicarboxylic acidselected from the group constituting of aromatic dicarboxylic acids suchas terephthalic acid, isophthalic acid, phthalic acid,naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid,diphenyl-4,4'-dicarboxylic acid, diphenoxyethane dicarboxylic acid,sodium-3-sulfoisophthalate, etc., alicyclic dicarboxylic acids such as1,4-cyclohexane dicarboxylic acid, aliphatic dicarboxylic acids such assuccinic acid, oxalic acid, adipic acid, sebacic acid, dodecane-diacid,dimeric acid, etc.; and their ester-forming derivatives; at least onediol component selected from the group consisting of aliphatic diolssuch as 1,4-buthanediol, ethylene glycol, trimethylene glycol,tetramethylene glycol, pentamethylene glycol, hexamethylene glycol,neopentyl glycol, decamethylene glycol, etc., alicyclic diols such as1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol,tricyclodecanedimethanol, etc., and their ester-forming derivatives; andat least one poly(alkylene oxide) glycol having an average molecularweight of about 400-5,000, selected from the group constituting ofpolyethlene glycol, poly(1,2- and 1,3-propyleneoxide) glycol,poly(tetramethylene oxide) glycol, or ethylene oxide/propylene oxidecopolymers, and ethylene oxide/tetrahydrofuran copolymers.

From a view to consideration of the adhesiveness to non-elastomeric,crimped, polyester, staple fibers, temperature characteristics andstrength, however, block copolymerized polyetherpolyesters arepreferred, in which polybutylene terephthalate serves as the hardsegment and polyoxybutylene glycol, as the soft segment. In this case,the polyester portion constituting the hard segment is composed ofpolybutylene terephthalate whose main acid component is terephthalicacid and main diol component is butylene glycol component. Naturally, apart (normally not more than 30 mole %) of the acid component may besubstituted with other dicarboxylic acid component or oxycarboxylic acidcomponent. Similarly, a part (normally not more than 30 mole %) of theglycol component may be substituted with dioxy component other than thebutylene glycol component.

The polyether portion constituting the soft segment can be composed ofthe polyethers substituted with a dioxy component other than butyleneglycol. The polymers may further contain various stabilizers,ultraviolet absorber, branching agent for increasing viscosity,delusterant, coloring agent and other various improvers as necessitatedin individual occasions.

Here, the fiber aggregation said above contains 10-70% of the binderfibers based on the weight of the fiber aggregate, preferably 20-60%,are mixed and dispersed into the matrix fibers, wherein said step iscarried out to evenly mix with a heap of the matrix fibers and that ofthe binder fibers with each other by supplying them through a cardingmachine.

Hereafter, a process and an apparatus for preparing a cushion structurefrom a fiber aggregate are explained in detail with drawings.

FIG. 1 is a front view which schematically shows an apparatus forpreparing a cushion structure from a fiber aggregate. In said figure, Fdenotes a fiber aggregate, and the others denote as follows: 1; aconveyor for carrying the fiber aggregate, 2; a loosening device forloosening the fiber aggregate, 3; a transfer duct for transporting thefiber aggregate, 4; a compression air supply device, 5; a mold frame, 6;a bottom mold, 7; a upper mold, 7a-7c; mold members divided the uppermold into, 8a-8d; actuators driven by the fluid pressure for moving theupper mold upward/downward, 9 and 10; an air exhaust device, 11; aheating air generator, and 12; exhaust chamber respectively. And, Cdenotes a mold cavity. In addition, symbol 20, shown by thin line,denotes the final shape of the molded cushion structure made of thefiber aggregate. But, such a cushion structure can be got after athermal process, as mentioned later, is completed.

In the apparatus, as mentioned above, a carding machine is convenientlyused as the loosening device 2 for loosening the fiber aggregate F,which has many needles 2b installed in an outer circumferential side ofa rotating cylinder. A means for supplying the fiber aggregate F to suchloosening device 2, as not specifically limited, is preferred to usesuch a device like a belt conveyor having a moving plane on which thefiber aggregate F is conveyed. Thus, the fiber aggregate F supplied tothe loosening device 2 by the conveyor 1 is combed by many needles 2bplanted onto the rotating cylinder 2a and loosened thereby. Thereafter,the loosened fiber aggregate F is supplied into the mold cavity Cthrough the transfer duct 3 which is connected with an exit of theloosening device 2 and an entrance of the mold frame 5, so that thefiber aggregate F is packed into the mold cavity C, where the aggregateis transferred by entrainment with compression air blown from on the wayof the transfer duct 3, and/or with the induced air by the rotatingcylinder 2a of the loosening device 2.

Here, in the present invention, it is very important that such a devicelike a blower, which generates air flow in the duct 3, must not bedirectly installed in on the way of the duct 3. When such a device isinstalled in on the way of the duct 3, a loosened state of the fiberaggregate is damaged by the impact struck by the rotors such as blower'simpellers which generate the air flow in the duct. As the result, thefiber aggregate filled up in the mold cavity C comes to have theloosening portions and the mal-loosening portions therein. When such asituation arises, the quality of the finally molded cushion structure isimpaired.

Furthermore, it is also important in the present invention that theupper mold 7, the bottom mold 6, and a part of mold frame 5 are havingthe gas-permeability. Because it is required that the blown compressionair for accompanying the fiber aggregate F into the mold cavity C mustbe quickly exhausted from the mold cavity C. When said compression airblown into the mold cavity may not be smoothly exhausted from the moldcavity C, it causes the turbulent air flow which makes it impossible tofill the fiber aggregate in selected portions of the mold cavity andpile it up therein under good condition. Further, as mentioned later,the gas-permeability of the mold is important element in order tosmoothly passing heating and cooling air through the fiber aggregate.

Next, the fiber aggregate is transported through the transfer duct byentrainment with the compression air, and is packed into the moldcavity, hereafter, the more detail of this aspect is explained referringto FIG. 2.

In the present invention, FIGS. 2(a) and 2(b) are both front views whichschematically show steps for filling up the mold cavity with the fiberaggregate by entrainment with compression air flow, and also show theaspects that the fiber aggregate is filled up from the farthest backpart of the mold cavity C, as shown in FIG. 2(a) through FIG. 2 (b) intime series.

This state is shown in FIG. 3, in which the fiber aggregate is fillingup into the mold cavity to go on accumulating, as forming layer-shapedaccumulation faces therein, and an aspect is also shown that the fiberaggregate goes on accumulating from the farthest back part of the moldcavity C to the mouth from which the fiber aggregate is blown (see inFIG. 3(a)). When the fiber aggregate F being in such a condition isturned into a cushion structure under the condition as it is without anyother condition, in-plane tearing strength along accumulating layerfaces becomes weaker, on the other hand the same along the right-angledfaces relative to the accumulating layer faces becomes stronger. When ithas anisotropic tearing strength, it impairs performance as a cushionstructure. Therefore, it is desirable for the cushion structure not tohave anisotropic tearing strength because it causes remarkably to impairthe performance in its tearing strength. And, the appearance of thecushion structure is damaged by striped surface where the sides of theaccumulation layers appear, and the condition of its surface finishingbecomes rough, so that it is not preferred.

From these reason said above, after the filling step into the moldcavity C is completed, the filled fiber aggregate F is sucked via thebottom mold 6, as shown in FIG. 3(b), so that orientation of suckedsurface portion of the fiber aggregate preferably goes along the surfaceshape of the mold. In addition, the space (which is exaggeratedly shownin FIG. 3(b) as it is), where the fiber aggregate is not packed, comesto be formed in the upper part of the mold cavity C because the fiberaggregate is downwardly compressed onto the bottom mold 6 by the airinduced by the suction from the bottom. After forming the fiberaggregate having such a sucked surface portion, by turning it into acushion structure, the cushion structure, in which destruction bytearing force may not widely spread even reaching to its surface, can berealized. Further, in order to break down the layer-shaped accumulationfaces formed during the filling process, it is effective to repeatedlycompress the fiber aggregate F by repeatedly traversing the upper mold 7downward/upward. In addition, in this case, it is more desirable thateach divided member (7a-7c) of the upper mold 7 may be independentlymoved upward/downward at random than all divided members can besynchronously moved all together.

In addition, the fiber aggregate F is compressed to the chosencompression ratio by the molds (6 and 7) installed in the top and thebottom part of the apparatus during or after filling step.

Hereafter, it is explained about a compressing operation of the fiberaggregate F filled up in the mold cavity which is formed by the bottommold 6 and the upper mold 7.

In the present invention, the side part of the mold cavity C filled withthe fiber aggregate is formed by the mold frame 5 which has the fullyopen top, the fully open bottom, and side wall fixed not to move freely.And, the bottom part of the mold cavity C is formed by the bottom mold 6movable upward/downward and making it possible to close the fully openbottom. Also, the top part of the mold cavity C is formed by the uppermold 7 divided into some mold members both independently andrespectively movable upward/downward and making it possible to close thefully open top. Therefore, in the state that the fiber aggregate isabout to be filled into the mold cavity C, as shown in FIG. 2(a), thebottom mold 6 and/or the upper mold 7 are preliminarily positioned tothe position where the mold cavity can have the bigger capacity thanthat of the cushion structure molded to the desired shape. Thereafter,under such a condition said above, the loosened fiber aggregateaccompanied with air flow is packed the mold cavity C with through thetransfer duct 3. Thus, the fiber aggregate filled up in the mold cavityC is compressed to the position by the bottom mold 6 and/or the uppermold where it has the desired bulk density.

Wherein, as means for moving the bottom mold 6 and the upper molddivided into some mold members (7a-7c) upward/downward, actuators(8a-8d) driven by fluid pressure such as publicly known air cylindersdriven by compression air are preferred. In addition, in said actuators(8a-8d), it is needless to say that, in order to compress the fiberaggregate to over multiple stages, they are installed in the positioningdevice (not shown in figure) for positioning the bottom mold 6 and/orthe upper mold divided into plural mold members to the selectedpositions. Further, in the present invention, it is also needless to saythat as the upper mold 7, only the mold members (7a˜7c) divided in thedepth direction of the mold cavity C is illustrated but it is possibleto divide it in the width direction of the mold cavity C.

However, by merely to move the bottom mold 6 and/or the upper mold, itis impossible to change partially the compression ratio of the fiberaggregate F and thereby also to change partially the density of thecushion structure. On the contrary, one of the features in the presentinvention is to be changeable the density of the fiber aggregate withoutwasting so much time when it would be partially changed.

In order to embody such things said above, in the present invention, itis quite important that the upper mold 7 is to be divided into theplural mold members (7a-7c) movable in the up-and-down directionrespectively and independently and thereby to close the opened top ofthe mold frame 5. Then, when each portion of the fiber aggregate isselectively compressed in the different ratio, it is easily realized toadjust strokes of the mold members in accordance with the eachcompression ratio of the each portion of the fiber aggregate by theexistence of the mold members movable upward/downward respectively andindependently. Namely, the divided mold members (7a-7c) of the uppermold 7 are preliminarily moved to the each position corresponding to theeach compression ratio in the fiber aggregate respectively beforefilling process begins and thereafter, in such a condition, the fiberaggregate is filled up in the mold cavity C, thus as a result, it isquite easily realized to partially change the bulk density of the fiberaggregate.

Beside, while the fiber aggregate F is compressed by the motion of themolds (6 and 7) it is possible to compress the fiber aggregate afterfilled up the mold cavity C, but, in the present invention, while thefilling process into the mold cavity is carried out, the each dividedmold member of the upper mold 7 is descended one after another from theback part of the mold cavity C where filling procedure is partlycompleted (shown in FIGS. 2(b) and 2(c)). By doing like this, a passagefor transferring the fiber aggregate through the back part of the moldcavity can be widely secured, and makes it possible to fill up smoothlythe back part of the mold cavity where evenly filling up is verydifficult.

And then, filling step into the mold cavity in the present inventionmakes it possible for the first time by pressing a fiber aggregate tothe back part of the mold cavity due to the action of the pressing forceof compression air. Therefore, in prior arts which such force do notact, it was very difficult to partially compress the fiber aggregatebecause the function, for maintaining the filling condition of the fiberaggregate as it is, may not work at all.

However, according to the method and/or the apparatus of the presentinvention, different from the prior arts, it does not need the injectorsfor transferring the fiber aggregate into the back part of the moldcavity and for distributing it onto it evenly, does not need to dispersethe transferred fiber aggregate by the action of the air flow, andfurther does not need to act the vacuum on every sides of the mold.Namely, the present invention only requires accompanied compression airflow in order to pack the mold cavity C with the fiber aggregate fromits back part.

In such a thing said above, it is quite important for the presentinvention that filling process is carried out so that thefiber-aggregate accompanied with the compression air flow is filled upthe mold cavity C not from a moving direction of the mold (6 and 7), butfrom a direction where it intersects with the right angle in the movingdirection of the mold (6 and 7). Thus, there are no filling means likeinjector to impede the movement of the bottom mold 6 and/or the top one7 in the mold cavity C during the filling process, so make it possibleto move them in the up-down direction freely at the desired timing.

Further, another feature of the present invention is that the adjustmentdevice for adjusting the mouth width of the transfer duct 3 is installedin the inside of the duct 3 positioned nearby the mold frame 5 for themold cavity C having plural different lengths relative to its back part.With regard to this, it explains in detail referring to the FIG. 4 and 5in the following as followed.

FIG. 4 is the enlarged perspective view which schematically shows theadjustment device 13 for adjusting mouth width of the transfer duct 3,and it allows to change its mouth width of the duct 3 so thatwidth-adjustable plates 13b swingable right and left are moved in theright or the left directions by a driving means 13a containing a powercylinder driven by fluid pressure. And then, as illustrated in FIGS.5(a) and (b), by installing in such device 13, the present inventionmakes it possible to fill up the mold cavity C with the fiber aggregateF selectively from the farthest back part (C1) of the mold cavity Cwithout an outbreak of voids, so that the mouth width of the duct 3 fortransporting the fiber aggregate F is changeable in accordance with itschanging front-edge width of the back part. If the fiber aggregate wasevenly filled up the mold cavity having both a farthest length (C1) anda short length (C2) relative to the back part of the mold cavity, apassage of the mold cavity where the fiber aggregate would pass throughtoward the farthest back part would be gradually narrowed by theaccumulation of the fiber aggregate supplied to the short length (shownin FIG. 5(d)). And, it may cause the outbreak of voids and unevenlyfilled bulk density because of insufficiently supplied fiber aggregate.Therefore, the above method is very effective in such a case that themold cavity has different lengths relative to its back part. Inaddition, in order to evenly fill up the mold cavity with the fiberaggregate F, it is preferred to preliminarily trimming it in accordancewith the back part shape of the mold cavity, placing it onto a conveyorbelt, and thereafter supplying it to a loosening device 2, as shown inFIG. 5 (c).

Here, on the occasion of filling up the mold cavity C with the fiberaggregate F, the ventilation of the compression air introduced into themold cavity C is smoothly carried out by installing in an auxiliary airexhaust device 10 confronting to an entrance of the gas-permeable moldframe 5 where a transfer duct 3 is connected. Then, it is preferred tofill up evenly at every corner of the mold cavity with the fiberaggregate without dirty spots. It is effective to use such an auxiliarymeans 10 together as the shape of the mold cavity C becomes complicatedone. Because, unless the compression air which has introduced into themold cavity in accompanied with the fiber aggregate F is smoothlyexhausted from the mold cavity C, such a compression air flow becomesturbulent flow, and therefore the position of the mold cavity where thefiber aggregate is accumulated and filled up cannot be controlledprecisely any more. On the contrary, the present invention makes itpossible to filled up at every corner of the mold cavity C with thefiber aggregate F without dirty spots so that the discharge of thecompression air from the mold cavity C can be intentionally controlledby the auxiliary air exhaust devices attached to the each portion of themold cavity C.

Next, when filling up the mold cavity C with the fiber-aggregate F saidabove is completed, the fiber aggregate is compressed by desired bulkdensity, and thereafter a thermal process for turning a fiber aggregateinto a cushion structure is started.

This thermal process, as being natural, contains both a heating processand a cooling one, because, in such a thermal process, the binder fiberscontained in the fiber aggregate are melted, and the fibers are bondedby the molten binder fibers as acting on the bonding agent, and finallyit is turned into a cushion structure. However, in this thermal process,it is necessary to take account of the peculiar character of the fiberaggregation. Namely, the fiber aggregate has extremely good property inits gas-permeability, then it is more effective to directly heat upand/or cool down the fiber aggregate filled up in the mold cavity by theheating and/or the cooling air penetrating through fibers thanindirectly heat up and/or cool down it by heating up and/or cooling downthe molds themselves. And, it also has an effect that it can be heatingup and/or cooled down the fiber aggregate uniformly by adopting thismethod.

By the way, the remarkable fact in the present invention is that theeach bulk density in the each portion of the fiber aggregate filled upin the mold cavity are partially changed to compress respectively by theeach divided member of the upper mold corresponding to its eachcompression ratio. Therefore, in the present invention, thegas-permeability of the gas-permeable molds becomes very importantelement in order that a heating air flow or a cooling one may penetratesmoothly through the fiber aggregate which bulk density is partlydifferent from. Because, when the bulk density of the fiber aggregate ispartly different, both easily gas-flowable part in the fiber aggregateand not easily gas-flowable one appear. When such a situation arises,heating dirty spots or cooling dirty spots appear in the fiber aggregateand it make it impossible to get a cushion structure of the uniformquality.

So to solve the above problem, the gas-permeability of the molds in thepresent invention are controlled by adjusting the distribution densityand/or hole sizes of the holes punched in the molds (see in FIG. 6(b)),on the other hand the conventional gas-permeable molds having theuniform gas-permeability are used even if which part of the molds istaken out (see in FIG. 6 (b)).

That is to say, the parts of the molds corresponding to the portion ofthe fiber-aggregate F having the higher compression ratio are adjustedto have high distribution density and/or large hole size in order toeasily pass through the molds, on the contrary, those corresponding tothe portion of the fiber-aggregate having the lower compression ratioare adjusted to have low distribution density and/or small hole size.Thus, it makes the heating or the cooling air equally easy to passthrough the fiber aggregate, so that the air is sufficiently supplied tothe portion where the air could not easily penetrate but the air supplyis limited to the portion where the excess air could easily penetrate.As a mold having such gas-permeability, sheet metal being punched a lotof holes, which is the works being bent in accordance with the destinedsurface shape of the cushion structure, is preferably used. And, amember having the gas-permeability, such as punching metal plate, metalwire netting, porous metal sinter, etc. can be suitably used,furthermore it is preferred that plural members among those may becombined and used it.

And, the heating air is supplied from the heating air generator 11 sothat it flows through the bottom mold 6, the fiber aggregate F filled upin the mold cavity, and the upper mold 7 respectively. Here, saidheating air generator 11 has the function both for heating up the air tothe destined temperature and for supplying it to the destined place. Atthis case, the air exhaust device 9 is operated at the same time, and bydoing like this the quantity of the heating air which flows through thefiber aggregate from its top side to the bottom one can be increased.Therefore, by using the heating air generator 11 and/or the air exhaustdevice 9, it allows that the heating air flows into the fiber aggregateF via the gas-permeable molds (6 and 7), and thereby the binder fiberscontained in the fiber aggregate F are melted, and thereafter the fiberscontained in the fiber aggregate are bonded with each other at theircrossing points by the molten binder fibers which act as bonding agent.

Wherein, the heating air flowing through the fiber aggregate is requiredto have great calorie in order to heat up the bottom mold 6, the uppermold 7, the mold frame 5, the fiber aggregate F, and so on in its earlyheating stage. Therefore, during the thermal process which turns thefiber aggregate F into the cushion structure 20, it is preferred thatquantities of heating air and/or the heating air heated in hightemperature is flowed through the fiber aggregate in the early stage ofthe heating process. This becomes possible to operate the heating airgenerator 11 and the air exhaust device 9 at the same time. And, in theearly stage, the temperature of the heating air makes higher than themelting temperature of the matrix fibers, but it is a premise that thetemperature of matrix fibers could not reach to their meltingtemperature. Therefore, in this case, before the temperature of thematrix fibers reach to the melting one, the heating air temperature mustbe preliminarily changed to the temperature, which is higher than themelting temperature of the binder fibers, and also which is lower thanthat of the matrix fibers.

In the early stage of this heating process, the matrix fibers containedin the fiber aggregate is in the condition of room temperature beforethe heating process, so it requires the time for rising the temperatureuntil a fiber aggregate reaches to its melting temperature. Then, thesituation that the matrix fibers may melt does not arise provided thatthe heating air, having the higher temperature than the melting one ofthe matrix fibers, is sent into the fiber aggregate. Therefore, in theearly stage of the heating process, it allows to send the heating air,having the higher temperature than the melting one of the matrix fibers,into the fiber-aggregate. But, when the heating air having such hightemperature is went on supplying until it becomes close to thecompletion stage of the heating process, the matrix fibers themselvescan be melted. Therefore, When the temperature of the matrix fibersapproach to the melting one, the time for turning into the cushionstructure is usually shortened, so that the heating air passing throughthe fiber aggregate is lowered to the temperature, which is higher thanthe melting temperature of the binder fibers and also which is lowerthan that of the matrix fibers, and/or so that the heating air quantityto be supplied into the fiber aggregate is also decreased over in themultiple stages. In addition, the timing switching the wind quantityand/or temperature of a heating air can be predicted to some extend bypreliminarily estimating the heat capacity of the mold, the fiberaggregate, and so on when it is designed. However, it is importantproper heat-treated condition is decided by execution of an experimentunder the condition that it is actually and finally filled up the moldcavity with the fiber aggregate. Moreover, relating to this heatingprocess, it is preferred that a heater is installed in the mold frame 5in order to heat up said mold frame 5 in the desired temperature.

During the thermal process said above, it is desirable to absorb theheat contraction of the fiber aggregate F in the heating and/or thecooling process by compressing the fiber aggregate to the position wherethe cushion structure is finally molded (compression condition in FIG.8), as a result of at least more than one time movement of the bottommold 6 and/or the upper mold 7 during the heating and/or cooling processof the fiber aggregate filled up in the mold cavity C, or after theheating process. Therefore, the compression of the fiber aggregatebefore the heating process must require to preliminarily set up room forcompression in order to compress it further during the heating and/orthe cooling process (see the compressed condition in FIG. 7). This,during heating process, is carried out in order to avoid the case thatit can't get the desired form of the cushion structure because of thethermal contracts of the heating fiber aggregate. And, this, during thecooling process, is also carried out in order to avoid the case that thecompressed fiber structure springs back and expands by retrieving theelasticity which is weakened by heating, wherein the binding force ofthe binder fibers, binding the fibers with each other, is also weakenedbecause the solidification of the binder is insufficient in this state.

When the heating process of the fiber aggregate F filled up in the moldcavity C therein is completed, the cooling process begins at once. Thiscooling process is carried out in order to retrieve the solidified statefrom the molten state of the binder fibers which combine the fibers inthe fiber aggregate with each other.

During this cooling process for solidifying the binder fibers, it isimportant to pass the cooling air, which is induced from the top of theupper mold 7 by the air exhaust device 9, through the heated fiberaggregate therein from the bottom side to the upper side of the moldcavity. Because the fiber aggregate F turned into the cushion structure20 is supported from the bottom side by the wind pressure of the coolingair, and therefore it makes it possible to attach the fiber aggregate tothe upper mold 7. Herein, a temperature of the cooling air is preferredto be at most 40° C., this temperature may well be as possible as lowertemperature in view of improving the cooling efficiency of the fiberaggregate F. But it is difficult to get the cooling air at a low price,so that, usually, air in the condition of the room temperature is oftenused as a cooling air.

While sustaining the state that the fiber aggregate is attached to theupper mold 7, the flow of the cooling air is stopped after the bottommold 6 is moved downward by the actuator 8a (namely, stop the operationof 9 or shut down the pipe way connecting to the air exhaust device). Bya series of procedures said above, the cushion structure 20, which iscompleted to cool down, falls downward due to the action of the gravity,because the wind pressure by the cooling air which is the source of thepower to attach it to the upper mold 7 has already disappeared.

In addition, related to this cooling process, the cushion structure 20can easily adhere to the upper mold 7, so that it occasionally causesthat the cushion structure 20 can not fall down only by the stop ofcooling air supply in the case that gravity is superior to the adhesivepower. Therefore, after the flow of the cooling air is stopped, as shownin the FIG. 9, the compression air supplied by the air spray nozzle 14is sprayed over the cushion structure 20 from the top of the upper mold7. By going on like said above, the cushion structure 20 can be releasedfrom the upper mold 7 easily by the action of the compression air.Moreover, it is preferred that some of the members of the mold membergroup (7a˜7c) thereof which the upper mold 7 is divided into are movedupward and/or downward, so that the cushion structure 20 is releasedfrom the upper mold 7. Thus, as shown in FIG. 9, the cushion structure20 is received onto the tray 15, which is movable to the position whereit may come to fall down, and by said tray 15, it is taken out from theapparatus for making a cushion structure.

We claim:
 1. A process for preparing a cushion structure using fiberaggregate, comprising(a) preparing a fiber aggregate by mixing anddispersing synthetic binder fibers into synthetic matrix fibers, whereinthe binder fibers are conjugated fibers composed of a binder componentand a non-binder component, wherein the binder component has a meltingpoint lower than that of the non-binder component and the matrix fibers;(b) loosening an amount of the fiber aggregate with a loosening device;(c) forming a mold cavity having a larger shape than that of a moldedcushion structure, wherein the mold cavity is defined by a gas-permeabletop mold movable upward and downward, a gas-permeable bottom moldmovable upward and downward, and a fixed mold frame; (d) filling themold cavity with the fiber aggregate by directly transporting theloosened fiber from the loosening device to the mold cavity with a flowof air; (e) compressing the fiber aggregate filled in the mold cavity bythe gas-permeable top and/or bottom mold until the compressed fiberaggregate attains a desired bulk density; (f) passing heated air throughthe compressed fiber aggregate via the gas-permeable top and bottom moldto fuse the binder component of the binder fibers so that the matrixfibers are bound with the molten binder fibers at their crossing pointsto form a heated fiber aggregate; (g) cooling the heated fiber aggregateby passing a cooling air so as to unite the matrix fibers withsolidified binder fibers; (h) removing a molded cushion structure fromthe mold cavity by a downward movement of the bottom mold.
 2. A processfor preparing cushion structure using fiber aggregate as set forth inclaim 1, wherein the matrix fibers are non-elastic, crimped polyesterstaple fibers.
 3. A process for preparing cushion structure using fiberaggregate as set forth in claim 1, in which said binder component is athermoplastic elastomer and said non-binder component is anon-elastomeric polyester, where the thermoplastic elastomer has amelting point of lower than that of the non-elastomeric polyester by atleast 40° C., and wherein the thermoplastic elastomer is exposed atleast at a half of the fiber surface.
 4. A process for preparing cushionstructure using fiber aggregate as set forth in claim 1, wherein saidfilling step (d) is carried out by transporting the loosened fiberaggregate through a transfer duct with an air flow blown into thetransfer duct by a blower and/or a rotating cylinder of the looseningdevice, and further said transporting is carried out without interposingany device in the transfer duct through the loosening device to the moldcavity.
 5. A process for preparing cushion structure using fiberaggregate as set forth in claim 1, wherein said top mold is divided intoplural mold members which are individually sequentially movable upwardand downward corresponding to each filled-up portion of the mold cavityso as to respectively compress said each filled-up portion to arespectively desired bulk density.
 6. A process for preparing cushionstructure using fiber aggregate as set forth in claim 5, wherein saideach bulk density of the compressed fiber aggregate is respectivelycontrolled by each movement of the divided mold members during and/orafter said filling step (d).
 7. A process for preparing cushionstructure using fiber aggregate as set forth in claim 1, furthercomprising:sucking air inside the mold cavity from the top and/or thebottom mold after said step (d), so that layers formed by accumulatedfiber aggregate are arranged so as to make them juxtaposed relative tothe mold surface.
 8. A process for preparing cushion structure usingfiber aggregate as set forth in claim 1, further comprising:repeatedlycompressing the fiber aggregate by the top and/or the bottom mold aftersaid step (d), so that an array of layers formed by accumulated fiberaggregate in the mold cavity are randomized by said repetitivecompressing of the filled-up fiber aggregate.
 9. A process for preparingcushion structure using fiber aggregate as set forth in claim 1, whereinsaid step (d) is carried out by adjusting a mouth width of a transferduct opened to the mold frame in accordance with a changing shape ofaccumulated fiber aggregate in the mold cavity, where the fiberaggregate is filled from a back part of the mold cavity.
 10. A processfor preparing cushion structure using fiber aggregate as set forth inclaim 1, wherein said filling step (d) is carried out by accompanyingthe fiber aggregate by an air flow which is blown into the mold cavitywith a right angle relative to a movable direction of the top and bottommold.
 11. A process for preparing cushion structure using fiberaggregate as set forth in claim 1, further comprising:exhausting the airblown into the mold cavity with the fiber aggregate from the mold cavityduring said filling step (d) by an exhaust device outside of the moldcavity.
 12. A process for preparing cushion structure using fiberaggregate as set forth in claim 1, wherein a gas-permeability of eachwall of said top and bottom mold is respectively adjusted correspondingto each flow resistance of filled-up portions of the mold cavity wherethe fiber aggregate is packed, so that the heating and cooling air canevenly pass through the fiber aggregate therein.
 13. A process forpreparing cushion structure using fiber aggregate as set forth in claim1, wherein mold walls of the top and bottom mold are perforated so as toadjust hole distribution densities and/or sizes of holes to control thegas-permeability of the mold walls.
 14. A process for preparing cushionstructure using fiber aggregate as set forth in claim 1, furthercomprising:during said step (f) and/or (g), moving the top and/or thebottom mold to a position where the fiber aggregate is finally molded asa cushion structure, so that a heat contraction of the molded cushionstructure is absorbed by the movement.
 15. A process for preparingcushion structure using fiber aggregate as set forth in claim 1, whereinsaid step (f) is carried out by changing an amount and/or a temperatureof the heated air passing through the fiber aggregate in multiplestages.
 16. A process for preparing cushion structure using fiberaggregate as set forth in claim 1, wherein said step (g) is carried outby passing the cooling air upward through the mold cavity from thebottom mold, so that said fiber aggregate stick to the top mold by thepressure of the cooling air.
 17. A process for preparing cushionstructure using fiber aggregate as set forth in claim 1, wherein, afterdownward moving of the bottom mold, said step (h) is carried out byspraying a compressed air from over the molded cushion structure via thetop mold so as to cause it to fall down, and thereafter taking out thefallen cushion structure.
 18. A process for preparing cushion structureusing fiber aggregate as set forth in claim 1, wherein said step (g) iscarried out by cooling air having a temperature of at most 40° C.
 19. Anapparatus for preparing a cushion structure from synthetic staple fiberaggregate having matrix fibers where binder fibers are dispersed andmixed, comprising the following elements (i)-(p):(i) a loosening devicefor loosening the fiber aggregate; (j) a fixed mold frame containing aside mold wall thereby, and further having open top and bottom ends; (k)a gas-permeable top mold containing a top wall, movable upward anddownward for closing the open top end of the mold frame; (l) agas-permeable bottom mold containing a bottom wall, movable upward anddownward for closing the open bottom end of the mold frame, and thegas-permeable bottom mold enables removal of the molded cushionstructure from a mold cavity by a downward movement; (m) a transfer ductfor transporting the fiber aggregate from the loosening device to a moldcavity which is defined by the side wall, the top wall, and the bottomwall; (n) a blower for supplying a pressurized air to the transfer ductso as to accompany the fiber aggregate with the pressurized air forfilling into the mold cavity; (o) a heating air generator for generatinga heated air which flows through the mold cavity filled-up with thefiber aggregate via gas-permeable top and bottom molds so as to melt thebinder fibers; and (p) a cooling air supply device for supplying acooling air which flows through the mold cavity filled-up with the fiberaggregate via gas-permeable top and bottom mold so as to solidify themolten binder fibers.
 20. An apparatus for preparing a cushion structureas set forth in claim 19, wherein the each wall of the gas-permeable topand bottom mold respectively has holes with desired distributiondensities and sizes in accordance with each bulk density of a filled-upportion of the fiber aggregate which is compressed by the top and/or thebottom mold.
 21. An apparatus for preparing a cushion structure as setforth in claim 19, further comprising;an adjustment device for adjustinga mouth width of the transfer duct in accordance with the changingfront-edge-width of a back part of the mold cavity, wherein the mouth ofthe transfer duct is opened to the mold frame.
 22. An apparatus forpreparing a cushion structure as set forth in claim 19 wherein thecooling air supply device has a function for passing the cooling airthrough the mold cavity from the bottom mold to the top mold.
 23. Anapparatus for preparing a cushion structure as set forth in claim 19further comprising;an auxiliary exhaust device, which is installed in agas-permeable side wall of the mold frame, for exhausting said air blowninto the cavity with the fiber aggregate.
 24. An apparatus for preparinga cushion structure as set forth in claim 23, wherein said auxiliaryexhaust device is installed in an outside of said gas-permeable sidewall of the mold frame for exhausting the blown air from the moldcavity.
 25. An apparatus for preparing a cushion structure as set forthin claim 19 further comprising;actuators for respectively independentlymoving each divided mold member of the top mold and the bottom moldupward and downward relative to the mold frame, wherein said eachactuator respectively has a positioning device for controlling eachposition for compressing the fiber aggregate over multiple stages. 26.An apparatus for preparing a cushion structure as set forth in claim 19further comprising;an air suction device for sucking air inside the moldcavity from the top and bottom mold through the fiber aggregate.
 27. Anapparatus for preparing a cushion structure as set forth in claim 19,further comprising;air spray nozzles for spraying compression air over amolded cushion structure from a top of the top mold.
 28. An apparatusfor preparing a cushion structure as set forth in claim 19 furthercomprising;a tray for receiving the falling molded cushion structure,wherein the tray is movable to an open space formed by a downward movingof the bottom mold.